include/linux/lm_interface.h

   1 /*
   2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
   3  * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
   4  *
   5  * This copyrighted material is made available to anyone wishing to use,
   6  * modify, copy, or redistribute it subject to the terms and conditions
   7  * of the GNU General Public License version 2.
   8  */
   9
  10 #ifndef __LM_INTERFACE_DOT_H__
  11 #define __LM_INTERFACE_DOT_H__
  12
  13
  14 typedef void (*lm_callback_t) (void *ptr, unsigned int type, void *data);
  15
  16 /*
  17  * lm_mount() flags
  18  *
  19  * LM_MFLAG_SPECTATOR
  20  * GFS is asking to join the filesystem's lockspace, but it doesn't want to
  21  * modify the filesystem.  The lock module shouldn't assign a journal to the FS
  22  * mount.  It shouldn't send recovery callbacks to the FS mount.  If the node
  23  * dies or withdraws, all locks can be wiped immediately.
  24  *
  25  * LM_MFLAG_CONV_NODROP
  26  * Do not allow the dlm to internally resolve conversion deadlocks by demoting
  27  * the lock to unlocked and then reacquiring it in the requested mode. Instead,
  28  * it should cancel the request and return LM_OUT_CONV_DEADLK.
  29  */
  30
  31 #define LM_MFLAG_SPECTATOR      0x00000001
  32 #define LM_MFLAG_CONV_NODROP    0x00000002
  33
  34 /*
  35  * lm_lockstruct flags
  36  *
  37  * LM_LSFLAG_LOCAL
  38  * The lock_nolock module returns LM_LSFLAG_LOCAL to GFS, indicating that GFS
  39  * can make single-node optimizations.
  40  */
  41
  42 #define LM_LSFLAG_LOCAL         0x00000001
  43
  44 /*
  45  * lm_lockname types
  46  */
  47
  48 #define LM_TYPE_RESERVED        0x00
  49 #define LM_TYPE_NONDISK         0x01
  50 #define LM_TYPE_INODE           0x02
  51 #define LM_TYPE_RGRP            0x03
  52 #define LM_TYPE_META            0x04
  53 #define LM_TYPE_IOPEN           0x05
  54 #define LM_TYPE_FLOCK           0x06
  55 #define LM_TYPE_PLOCK           0x07
  56 #define LM_TYPE_QUOTA           0x08
  57 #define LM_TYPE_JOURNAL         0x09
  58
  59 /*
  60  * lm_lock() states
  61  *
  62  * SHARED is compatible with SHARED, not with DEFERRED or EX.
  63  * DEFERRED is compatible with DEFERRED, not with SHARED or EX.
  64  */
  65
  66 #define LM_ST_UNLOCKED          0
  67 #define LM_ST_EXCLUSIVE         1
  68 #define LM_ST_DEFERRED          2
  69 #define LM_ST_SHARED            3
  70
  71 /*
  72  * lm_lock() flags
  73  *
  74  * LM_FLAG_TRY
  75  * Don't wait to acquire the lock if it can't be granted immediately.
  76  *
  77  * LM_FLAG_TRY_1CB
  78  * Send one blocking callback if TRY is set and the lock is not granted.
  79  *
  80  * LM_FLAG_NOEXP
  81  * GFS sets this flag on lock requests it makes while doing journal recovery.
  82  * These special requests should not be blocked due to the recovery like
  83  * ordinary locks would be.
  84  *
  85  * LM_FLAG_ANY
  86  * A SHARED request may also be granted in DEFERRED, or a DEFERRED request may
  87  * also be granted in SHARED.  The preferred state is whichever is compatible
  88  * with other granted locks, or the specified state if no other locks exist.
  89  *
  90  * LM_FLAG_PRIORITY
  91  * Override fairness considerations.  Suppose a lock is held in a shared state
  92  * and there is a pending request for the deferred state.  A shared lock
  93  * request with the priority flag would be allowed to bypass the deferred
  94  * request and directly join the other shared lock.  A shared lock request
  95  * without the priority flag might be forced to wait until the deferred
  96  * requested had acquired and released the lock.
  97  */
  98
  99 #define LM_FLAG_TRY             0x00000001
 100 #define LM_FLAG_TRY_1CB         0x00000002
 101 #define LM_FLAG_NOEXP           0x00000004
 102 #define LM_FLAG_ANY             0x00000008
 103 #define LM_FLAG_PRIORITY        0x00000010
 104
 105 /*
 106  * lm_lock() and lm_async_cb return flags
 107  *
 108  * LM_OUT_ST_MASK
 109  * Masks the lower two bits of lock state in the returned value.
 110  *
 111  * LM_OUT_CACHEABLE
 112  * The lock hasn't been released so GFS can continue to cache data for it.
 113  *
 114  * LM_OUT_CANCELED
 115  * The lock request was canceled.
 116  *
 117  * LM_OUT_ASYNC
 118  * The result of the request will be returned in an LM_CB_ASYNC callback.
 119  *
 120  * LM_OUT_CONV_DEADLK
 121  * The lock request was canceled do to a conversion deadlock.
 122  */
 123
 124 #define LM_OUT_ST_MASK          0x00000003
 125 #define LM_OUT_CACHEABLE        0x00000004
 126 #define LM_OUT_CANCELED         0x00000008
 127 #define LM_OUT_ASYNC            0x00000080
 128 #define LM_OUT_ERROR            0x00000100
 129 #define LM_OUT_CONV_DEADLK      0x00000200
 130
 131 /*
 132  * lm_callback_t types
 133  *
 134  * LM_CB_NEED_E LM_CB_NEED_D LM_CB_NEED_S
 135  * Blocking callback, a remote node is requesting the given lock in
 136  * EXCLUSIVE, DEFERRED, or SHARED.
 137  *
 138  * LM_CB_NEED_RECOVERY
 139  * The given journal needs to be recovered.
 140  *
 141  * LM_CB_DROPLOCKS
 142  * Reduce the number of cached locks.
 143  *
 144  * LM_CB_ASYNC
 145  * The given lock has been granted.
 146  */
 147
 148 #define LM_CB_NEED_E            257
 149 #define LM_CB_NEED_D            258
 150 #define LM_CB_NEED_S            259
 151 #define LM_CB_NEED_RECOVERY     260
 152 #define LM_CB_DROPLOCKS         261
 153 #define LM_CB_ASYNC             262
 154
 155 /*
 156  * lm_recovery_done() messages
 157  */
 158
 159 #define LM_RD_GAVEUP            308
 160 #define LM_RD_SUCCESS           309
 161
 162
 163 struct lm_lockname {
 164         u64 ln_number;
 165         unsigned int ln_type;
 166 };
 167
 168 #define lm_name_equal(name1, name2) \
 169         (((name1)->ln_number == (name2)->ln_number) && \
 170          ((name1)->ln_type == (name2)->ln_type)) \
 171
 172 struct lm_async_cb {
 173         struct lm_lockname lc_name;
 174         int lc_ret;
 175 };
 176
 177 struct lm_lockstruct;
 178
 179 struct lm_lockops {
 180         const char *lm_proto_name;
 181
 182         /*
 183          * Mount/Unmount
 184          */
 185
 186         int (*lm_mount) (char *table_name, char *host_data,
 187                          lm_callback_t cb, void *cb_data,
 188                          unsigned int min_lvb_size, int flags,
 189                          struct lm_lockstruct *lockstruct,
 190                          struct kobject *fskobj);
 191
 192         void (*lm_others_may_mount) (void *lockspace);
 193
 194         void (*lm_unmount) (void *lockspace);
 195
 196         void (*lm_withdraw) (void *lockspace);
 197
 198         /*
 199          * Lock oriented operations
 200          */
 201
 202         int (*lm_get_lock) (void *lockspace, struct lm_lockname *name, void **lockp);
 203
 204         void (*lm_put_lock) (void *lock);
 205
 206         unsigned int (*lm_lock) (void *lock, unsigned int cur_state,
 207                                  unsigned int req_state, unsigned int flags);
 208
 209         unsigned int (*lm_unlock) (void *lock, unsigned int cur_state);
 210
 211         void (*lm_cancel) (void *lock);
 212
 213         int (*lm_hold_lvb) (void *lock, char **lvbp);
 214         void (*lm_unhold_lvb) (void *lock, char *lvb);
 215
 216         /*
 217          * Posix Lock oriented operations
 218          */
 219
 220         int (*lm_plock_get) (void *lockspace, struct lm_lockname *name,
 221                              struct file *file, struct file_lock *fl);
 222
 223         int (*lm_plock) (void *lockspace, struct lm_lockname *name,
 224                          struct file *file, int cmd, struct file_lock *fl);
 225
 226         int (*lm_punlock) (void *lockspace, struct lm_lockname *name,
 227                            struct file *file, struct file_lock *fl);
 228
 229         /*
 230          * Client oriented operations
 231          */
 232
 233         void (*lm_recovery_done) (void *lockspace, unsigned int jid,
 234                                   unsigned int message);
 235
 236         struct module *lm_owner;
 237 };
 238
 239 /*
 240  * lm_mount() return values
 241  *
 242  * ls_jid - the journal ID this node should use
 243  * ls_first - this node is the first to mount the file system
 244  * ls_lvb_size - size in bytes of lock value blocks
 245  * ls_lockspace - lock module's context for this file system
 246  * ls_ops - lock module's functions
 247  * ls_flags - lock module features
 248  */
 249
 250 struct lm_lockstruct {
 251         unsigned int ls_jid;
 252         unsigned int ls_first;
 253         unsigned int ls_lvb_size;
 254         void *ls_lockspace;
 255         const struct lm_lockops *ls_ops;
 256         int ls_flags;
 257 };
 258
 259 /*
 260  * Lock module bottom interface.  A lock module makes itself available to GFS
 261  * with these functions.
 262  */
 263
 264 int gfs2_register_lockproto(const struct lm_lockops *proto);
 265 void gfs2_unregister_lockproto(const struct lm_lockops *proto);
 266
 267 /*
 268  * Lock module top interface.  GFS calls these functions when mounting or
 269  * unmounting a file system.
 270  */
 271
 272 int gfs2_mount_lockproto(char *proto_name, char *table_name, char *host_data,
 273                          lm_callback_t cb, void *cb_data,
 274                          unsigned int min_lvb_size, int flags,
 275                          struct lm_lockstruct *lockstruct,
 276                          struct kobject *fskobj);
 277
 278 void gfs2_unmount_lockproto(struct lm_lockstruct *lockstruct);
 279
 280 void gfs2_withdraw_lockproto(struct lm_lockstruct *lockstruct);
 281
 282 #endif /* __LM_INTERFACE_DOT_H__ */
 283